Hello and Welcome Carlos,
You have certainly proved to be resilient! What an incredible story about second chances. I cannot speak to gastric bypass but compared to what you've been through it will hopefully be relatively minor. Keep taking good care of yourself and working on your mobility. I spent a year on a scooter with 9 months on crutches before walking again after a nerve injury and 3 operations. Gains do come with time and effort.
I hope your procedure goes smoothly and you find continued healing and improvement,